Doctor system suction apparatus



Sept. 1, 1970 w. KLEIMOLA DOCTOR SYSTEM SUCTION APPARATUS Filed Nov. 14,1966 FIG 2 United States Patent O 3,526,017 DOCTOR SYSTEM SUCTIONAPPARATUS William Kleimola, East Walpole, Mass., assignor to BirdMachine Company, South Walpole, Mass., a corporation of MassachusettsFiled Nov. 14, 1966, Ser. No. 594,111 Int. Cl. D21g 3/00 US. Cl. 15308Claims ABSTRACT OF THE DISCLOSURE A suction nozzle is mountable along adoctor blade to provide an inlet for removing debris from the surface ofthe doctor blade, and a blowback discharge member located interiorly ofthe suction nozzle for intermittent operation to dislodge accumulationsof debris blocking the inlet. A removable clean-out tool is provided forsliding along the nozzle.

This invention relates to doctoring systems for papermaking machines andmore particularly to suction apparatus for removing from the doctoringarea paper particles and fibers loosened from the machine rolls bydoctor blades.

Suction apparatus of the type concerned is equipped with an inlet nozzleclosely overlying the associated doctor blade which nozzle tends tobecome plugged with accumulations of paper fibers or pieces,particularly those of large size or which are wet and sticky. Withexisting apparatus such plugging accumulations increase in extentrapidly, correspondingly reducing the efficiency of removal until theaparatus becomes essentially inoperative. To remedy this condition it isnecessary to stop the machine and manually clear the nozzle obstruction,which is not only a difiicult, time consuming task but also idles thewhole machine, thereby increasing production cost.

A primary object of this invention is to solve this problem by providinga simple, inexpensive, suction apparatus for doctoring systems inpapermaking machines, which periodically removes and eliminates suchaccumulations of paper particles and similar debris in the suctionnozzle, while the machine is running, without the necessity of manualintervention. This object is effected by providing within the suctionnozzle, blowback means which periodically and momentarily blasts fluid,normally air under superatrnospheric pressure, toward and out the nozzleinlet to break up and dislodge the plugging accumulations so that theycan be thereafter removed by the suction system.

In certain applications of the suction apparatus of the invention,particularly to the doctors of rolls adjacent the wet end of thepapermaking machine, plugging accumulations or large sized pieces ofpaper become so wedged within the nozzle inlet that they are notdislodged by the blowback pressure. For such applications the inventionprovides as an additional feature a special clean-out tool and withinthe suction nozzle means for guiding the tool so that it may be readilyslid along the nozzle and is operable to aid the blowback in ejectingsuch obstructions from the nozzle inlet.

Although it is not necessary to do so, it is preferred to provide thedoctor blade, its holder and support, and the suction nozzle with itsmanifold as a single assembly, the doctor blade, its holder and supportforming the bottom of the suction nozzle.

Other objects, features, and advantages will appear from the followingdescription of preferred embodiments of the invention, taken togetherwith the attached drawings thereof, in which:

FIG. 1 is a partially broken-away perspective view of ice a portion of aroll and of a doctoring system combined with suction apparatus equippedwith the blowback feature of the invention;

FIG. 2 is a plan view of apparatus according to FIG. 1 modified toreceive and guide a manual clean-out assistance tool shown in use;

FIG. 3 is a transverse vertical cross-section on lines 33 of FIG. 2,looking in the direction of the arrows, and

FIG. 4 is a perspective view of the tool shown in FIGS. 2 and 3.

Referring to FIG. 1 a papermaking machine roll 10 is shown as doctoredby doctor blade 12 mounted on a fixed supporting ledge 14 by a suitableholder assembly, the ledge '14 and holder assembly constituting meansfor supporting the doctor blade in doctoring position. The holderassembly shown includes a top holder plate 16 removably fastened toledge I14, a bottom holder plate 18 removably fastened to plate 16 andchanneled to receive therein the rear end of the doctor blade, and akeeper spring plate 20 having its rear end held between the front end ofplate .16, which is beveled downwardly as shown at 22, and the rear endof plate 18, and has its front end overlying and retaining the rear endof doctor blade 12.

As is preferred, the suction apparatus has the bottom of its intakenozzle, designated generally 24, formed by the doctor blade and holderassembly, which serves to locate the nozzle inlet directly on the doctorblade where it is most efiicient. Supporting ledge 14 is convenientlyformed, as shown, as an integral part of the suction manifold 26, whichis pivotally mounted in bearing supports at its ends (not shown) andconnected to a suitable source of suction such as a vacuum pump (notshown). The top of the nozzle is formed of a curved plate or hood 28removably fastened to manifold 26 by bolts 29 received in threadedapertures (not shown) in the underlying wall (said bolts and manifoldthereby constituting means for mounting said hood), with its rear edgeengaging the manifold, curving outwardly therefrom to a forwardly anddownwardly extending portion terminating in a front end 30. End 30overlies the rear end of the doctor blade and has a flat undersurfacedrearward extension 3-2 which overlies the front end of plate 22 andterminates in a rear end spaced from beveled end 22 of plate 16. End 30and the under surface of extension 32 form with doctor blade '12, plate20 and beveled end 22, the nozzle inlet slot to an interior ofsubstantial size between plate 16, ledge I14 and hood 28. A plurality ofopenings 34 extend through the wall portion of manifold 26 exposed tothis interior and spaced longitudinally thereof.

Preferably, as shown, the interior of nozzle 24 is divided into aplurality of inlet compartments, one for each opening 34, by pairs ofside walls 36 carried by hood 28. The walls of each pair are contiguousto opening 34 at their rearward ends and slant laterally in oppositedirections to join at their front ends the oppositely slanted wall ofthe next pair in a single thin tip 38 which underlies end 30 andextension 32 of hood 28, with only sufficient clearance above doctorblade 12 and plate 20 to permit the requisite upward flexibility ofthese parts. Tips 38 and additional thin ribs 40 extending down from theunder surface of extension 32 function to prevent large pieces of paperfrom being sucked into the nozzle.

In accordance with the invention the suction nozzle is equipped withblowback means shown as comprising a manifold 42 mounted under ledge 14,the manifold being connected by pipe 44 to a suitable source (not shown)of fluid under pressure, preferably compressed air. Pipe 44 is providedwith an open and shut valve 46 which may be operated by a solenoid 48.Manifold 42 is provided with a plurality of jet nozzles designatedgenerally 50 which extend upwardly therefrom through apertures in ledge14 into the interior of nozzle 24, there being one jet nozzle providedfor each inlet compartment formed by walls 36 within nozzle 24.

Jet nozzles 50 may 'be conveniently and efficiently formed as shown of aconventional bolt '52, the head of which is located in the inletcompartments of nozzle 24, the shank of which extends through bores inledge 14 and the top and bottom of manifold 42 to which it is fastenedby nut 54, and which has a cutaway front portion 56 in its shank andunderside of its head facing the nozzle inlet, the cutaway portionextending from within manifold 42, through the bores in the top thereofand in ledge 14 to the cutaway portion of the bolt head which faces thenozzle inlet. Thus there is formed a passage into the jet nozzle betweenthe cutaway portion 56 of each bolt 52 and the bores through which itextends in the top of manifold 42 and ledge 14. Through this passagepressurized fluid may pass to impinge upon the flat under side of thecutaway front portion of the bolt head, the rear end of which is seatedon ledge 14. The fluid is directed by the flat surfaces of the bolthead, and of the wall of the cutaway portion of the shank of bolt 52extending above ledge 14, in a fan-shaped jet toward the suction nozzleinlet and substantially uniformly between the ends 38 of the side wallsdefining the compartment containing the blowback jet nozzle 50, as isimportant in obtaining efiicient operation of the blowback pressure.

In operating the apparatus of FIG. 1, manifold 26 is normallycontinuously connected to suction so that paper particles scraped ontodoctor blade 12 are continuously sucked therefrom into nozzle 24 and outthrough opening 34 into manifold 26, from Which they are withdrawn bythe suction system for disposal. Valve 46 in feed line 44 to pressuremanifold 42 is normally kept closed but at selected intervals ismomentarily opened to permit compressed fluid to flow from the jetnozzles 50 toward and out said inlet in a reverse flow to the flOlW ofair and debris into said inlet, to break up any blowback particleaccumulations in the inlets to suction nozzle 2-4 so that, upon shuttingoff of the pressure system, they may be drawn into the suction nozzleand disposed of. Means is provided for intermittently operating saidblowback means to dislodge blocking accumulation of debris from saidinlet in the form of a valve 46 which may be manually controlled as by aswitch (not shown) in the electric connections to solenoid 48. However,it is preferred to operate valve 46 automatically by timing mechanism(not shown) which periodically opens the valve for a brief intervalsuflicient to blow out obstructions and then closes it. The timeintervals between blowback operation and the duration thereof should besuch as to prevent any major plugging. of the suction nozzle and toinsure that under normal conditions all blockages that have occurred areeliminated. In this way the suction apparatus can be kept runningcontinuously at substantially full efiiciency without the necessity ofstopping the machine for manual cleanout under normal conditions.

The amount of suction maintained and the amount of blowback pressure arevariables depending on the particular application of the equipment. In atypical installation, suction is maintained by a subatmospheric pressurein manifold 26 of the order of about an inch of mercury or less, andblowback fluid is supplied at a superatrnospheric pressure of about 30to 50 p.s.i.

As previously stated, plugging material may occasionally become sowedged in the suction nozzle inlet that it is not dislodged by theblowback fluid, particularly at the wet end of the paper machine. Forinstallations where this condition may occur, I prefer to provide themodified suction manifold construction of FIGS. 2 and 3 to enable theuse of the clean-out tool shown particularly in FIG. 4.

FIGS. 2 and 3, wherein parts the same as in FIG. 1 are designated byprimes of the same reference numerals, show the apparatus of FIG. 1modified only by the provision of a vertically disposed groove 60 in theunderside of hood 28 extending the full length of the hood in thevicinity of the rear edge of extensions 32', and by the addition of themanually operated cleaning tool. Referring to FIGS. 2 and 3 it will beseen that the groove 60 extends through the inner. ends of exten sions32' and of ribs 40 and also through walls 36 to provide a continuoustrack in which an inner positioning flange 62 of the tool may slide. Asbest shown in FIGS. 3 and 4 the tool, in its preferred form there shown,may ccmprise a substantially vertically disposed strip 64 of thin gaugemetal having a rearwardly extending portion 66 at its under edge whichcarries at its inner edge positioning flange 62, portion 66 being thinenough to slide under the clearance between the underparts of suctionnozzle hood 28' and the doctor blade assembly. The opposite ends 62' and62" of flange 62, 66 and 66" of portion 66 are oppositely inclined fromtheir upper and inner ends respectively, so that as the tool is slidlongitudinally of nozzle 24' in either direction the end of flange 62 inthe direction of movement of the tool will plow downwardly out of slot60 any accumulation of paper particles therein and the corresponding endof portion 66 will similarly plow accumulations under the nozzle inlettoward and out of its front end. An elongated handle 68 is pivotallymounted on bolt 70 fixed centrally of the tool strip 64, the handleextending longitudinally of the suction device and being longer than thesuction device-doctor assembly so that the tool may be inserted at oneend of the assembly and slid via the handle completely from end to endof the assembly.

FIG. 4 shows the tool conveniently made by cutting and bending a stripof light gauge metal to provide portion 66 bent rearwardly and guideflange 62 bent upwardly from the rearward edge of portion 66. Frontalreinforcing projections 72 are formed by bending forwardly the metaladjacent the portions cut away to form the ends of portion 66 and flange62, and a top reinforcing frontal projection 74 is formed by bending thetop of the metal strip forwardly.

If the suction nozzle becomes so plugged that the blowback means willnot dislodge the plugging material, the tool of the modificationillustrated in FIGS. 2-4 may be utilized to remove the obstructionswhich are wedged in the suction nozzle inlet. To accomplish thisobjective, the suction system'is normally shut off and the blowbackpressure system is turned on as by a manually controlled switch (notshown) in the circuit to solenoid 48. The cleanout tool is then insertedat one end of the apparatus with flange 62 in groove 60 and pushed backand forth through the apparatus by means of elongated handle 68 untilthe wedged obstructions are cleared out the front of the inlet to thesuction apparatus, with the aid of the blowback pressure. This operationmay or may not require shutting down the papermaking machine, dependingupon whether the angle of removal of the paper from roll 10 over doctorblade 12 is great enough to accommodate the cleanout tool beneath it.

Having described and illustrated preferred embodiments of the invention,I claim:

1. Doctoring apparatus including apparatus for removing from thevicinity of a doctor blade debris such as paper particles scraped from aroll by said blade, which comprises a doctor blade, means for supportingsaid doctor blade in doctoring position, a suction nozzle overlying saidsupporting means and having a top hood and a hollow interior, an inletto said nozzle interior comprising an extension of said hood overlyingsaid doctor blade, means for mounting said hood so that said inlet isexposed to the debris on said doctor blade, opening means for connectingsaid nozzle to a source of subatmospheric pressure to suck air and saiddebris into said interior through said inlet, blowback means in theinterior of said nozzle for discharging. fluid under superatmosphericpressure interiorly of said inlet toward and out said inlet in a reverseflow to the flow of air and debris into said inlet, and means forintermittently operating said blowback means to dislodge blockingaccumulations of debris from said inlet.

2. Apparatus according to claim 1 wherein said nozzle is interiorlyprovided with walls forming a plurality of compartments spacedlongitudinally of said blade, separate opening means for connecting eachcompartment to said subatmospheric'pressure, and separate blowback meansin the interior of each compartment for discharging fluid undersuperatmospheric pressure interiorly of said nozzle and inwardly of saidinlet toward and out said inlet in a reverse flow to the flow of air anddebris into said inlet, and means for intermittently operating saidblowback means to dislodge blocking accumulations of debris from saidinlet.

3. Apparatus according to claim 2 wherein said blowback means comprisesa manifold connected to a source of fluid under pressure and a jetnozzle in each said com partment connected to receive fluid from saidmanifold and to direct it substantially uniformly to the suction nozzleinlet for each compartment.

4. Apparatus according to claim 1 wherein the extension of said hood isprovided with a slot extending longitudinally of said nozzle and whichincludes a slideable cleanout tool having a flange received in saidslot, said flange connected to a portion which slides through saidnozzle inlet for plowing accumulation of debris from said inlet, saidtool being provided with means for sliding it longitudinally of saidnozzle inlet.

5. Apparatus according to claim 4 wherein said tool flange and portionhave ends, said ends being oppositely inclined to plow. debrisaccumulations outwardly from said slot and inlet when slid in therespective directions of such ends and longitudinally of said nozzleinlet.

References Cited UNITED STATES PATENTS 8/1966 Scott 15--256.5 XR 5/1965Goyette 15----256.5 XR

